Severe Acute Respiratory Syndrome (SARS) is an emerging infectious disease with a high lethality caused by the novel SARS coronavirus (SARS-CoV). Since the outbreak of the disease in 2003 in China, not less than 8000 people have been infected and about 800 people have died. However, no effective prophylactic or therapeutic method for the disease exists so far. After the outbreak of SARS, the SARS virus, which is the causative virus of SARS, was identified (Non-patent Document 1), and its base sequence has been determined (Non-patent Document 2).
The SARS coronavirus is a novel species of coronavirus belonging to Coronaviridae, a group of single-stranded (+) RNA viruses. The genome size of the SARS coronavirus is 29.7 kb, which is very large (Non-patent Document 2), and the genome encodes 23 putative proteins. As major structural proteins, there are Spike (1256 aa), Nucleocapsid (423 aa), Membrane (222 aa) and Small Envelope (77 aa). As nonstructural proteins, there are two polyproteins pp1a (4382 aa, SEQ ID NO:31; GenBank Accession No. AAP13439) and pp1b (2696 aa), and from these polyproteins, individual proteins are cleaved out by proteases in a site-specific manner.